the Curtain


of Single Crystal Casting


While single crystal casting is primarily used for turbine blades, a few other demanding applications could benefit from the secretive process.


Shea Gibbs, Senior Editor


tor wanting for a view of the pouring area. Another industry leader, Preci- sion Castparts Corp., Portland, Ore., typically won’t let outsiders even that close—the company has repeatedly turned down requests for comments and tours. And a turbine parts OEM that recently expanded its in-house


T


urbine blade producers leave nothing to chance. A tour of Alcoa How-


met’s Whitehall, Mich., plant will leave the visi-


casting capabilities, Chromalloy, Palm Beach Gardens, Fla., curtained off mul- tiple areas of its plant during its grand opening ceremonies on Dec. 2, 2010. “We’re just a little careful, let’s say,”


said Andrew Farrant, Chromalloy’s vice president of marketing and corporate communications. The three companies make parts


for aerospace and power generation turbines. The castings used in the applications generally are produced in nickel-based superalloys and can


36 Metal Casting Design anD PurChasing


take on one of three microstructural orientations—equiaxed, directionally solidified or single crystal. Single crystal castings are the Ca-


dillacs of the group. Because of their boundary free grain orientation (see sidebar “Explaining Cast Microstruc- tures” for a primer on metallography), the parts are stronger and more heat resistant than castings with more con- ventional microstructures. “Single crystal castings are uniquely difficult to manufacture,” said Paul


May/June 2011


Behind


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60